Multiplanar probe for ultrasonic imaging

Abstract

A multiplanar ultrasonic probe incorporates a mechanically rotatable linear phased transducer array. The transducer array can be remotely maneuvered to change the scan plane. A ring gear affixed to the transducer array surrounds the transducer array and is concentric with the axis of rotation. The ring gear is engaged and rotated by an indexing mechanism in incremental angular steps in either the clockwise or counterclockwise direction. The indexing mechanism includes a ratchet mechanism displaceable along a line between first and second positions from a neutral position intermediate the first and second positions. The ratchet mechanism carries a pair of pawls, one of which engages the ring gear to cause clockwise rotation and the other of which engages the ring gear to cause counterclockwise rotation. The ratchet mechanism is displaced by actuators such as bimorphic devices, made of piezoelectric material, which bend in response to electrical pulsing.

What is claimed is: 
     
       1. A multiplanar probe comprising, an array of ultrasonic transducers, each of said transducers including an output electrode, said probe further comprising means for rotating the transducer array about an axis of rotation, the rotating means comprising a ring gear affixed to said transducer array, said ring gear having a plurality of teeth distributed at equal angular intervals on its periphery, and indexing means for driving said ring gear to rotate in angular steps, said indexing means comprising a ratchet mechanism having first and second pawls, and means for displacing said ratchet mechanism between first and second positions, said first pawl being engaged with said teeth of said ring gear and said second pawl being disengaged from said teeth of said ring gear when said ratchet mechanism is in said first position, and said first pawl being disengaged from said teeth of said ring gear and said second pawl being engaged with said teeth of said ring gear when said ratchet mechanism is in said second position, a flexible printed circuit board having terminals thereon, and means coupling said terminals to the output electrodes of the transducer array. 
     
     
       2. The multiplanar probe as defined in claim 1, wherein said means for displacing said ratchet mechanism comprises first and second bimorphic devices, each of said bimorphic devices being comprised of piezoelectric material which bends in response to application of an electrical pulse thereto, said first and second bimorphic devices being arranged to displace said ratchet mechanism between said first and second positions in response to electrical pulses applied thereto. 
     
     
       3. The multiplanar probe as defined in claim 2, further comprising detent means for preventing rotation of said ring gear during intervals between successive indexing steps, and spring means for urging said detent means into engagement with said teeth of said ring gear. 
     
     
       4. A multiplanar probe comprising, an array of ultrasonic transducers, each of said transducers including an output electrode, said probe further comprising: means for rotating the transducer array about an axis of rotation, the rotating means comprising a ring gear affixed to said transducer array, said ring gear having a plurality of teeth distributed at equal angular intervals on its periphery, and indexing means for driving said ring gear to rotate in angular steps;   a flexible printed circuit board having terminals thereon;   means coupling said terminals to the output electrodes of the transducer array;   a housing, said probe being situated within said housing;   array stop means mounted on said periphery of said ring gear and extending radially outward beyond the radial extent of said teeth;   first and second stop pins mounted on said housing, said first stop pin being arranged to engage said array stop means when said transducer array is at a first angular position and said second stop pin being arranged to engage said array stop means when said transducer array is at a second angular position; and   feedback means for signaling impingement of said array stop means on said first or second stop pin to prevent actuation of said indexing means to rotate said ring gear beyond said first or second stop pin, respectively.   
     
     
       5. A multiplanar probe comprising, an array of ultrasonic transducers, each of said transducers including an output electrode, said probe further comprising: means for rotating the transducer array about an axis of rotation, the rotating means comprising a ring gear affixed to said transducer array, said ring gear having a plurality of teeth distributed at equal angular intervals on its periphery, and indexing means for driving said ring gear to rotate in angular steps;   a flexible printed circuit board having terminals thereon;   means coupling said terminals to the output electrodes of the transducer array:   a housing, said probe being situated within said housing;   array stop means mounted on said periphery of said ring gear and extending radially outward beyond the radial extent of said teeth;   first and second stop pins mounted on said housing, said first stop pin being arranged to engage said array stop means when said transducer array is at a first angular position and said second stop pin being arranged to engage said array stop means when said transducer array is at a second angular position;   feedback means for signaling impingement of said array stop means on said first or second stop pin to prevent actuation of said indexing means to rotate said ring gear beyond said first or second stop pint respectively; and   position encoding means for detecting the angular position of said transducer array.   
     
     
       6. A multiplanar probe comprising, an array of ultrasonic transducers, each of said transducers including an output electrode, said probe further comprising a ring gear affixed to said transducer array for rotating the transducer array about an axis of rotation, said ring gear being connected to said array and having a plurality of teeth distributed at equal angular intervals on its periphery, and indexing means for driving said ring gear to rotate in angular steps, said indexing means comprising a ratchet mechanism having first and second pawls, and means for displacing said ratchet mechanism between first and second positions, said first pawl being engaged with said teeth of said ring gear and said second pawl being disengaged from said teeth of said ring gear when said ratchet mechanism is in said first position, and said first pawl being disengaged from said teeth of said ring gear and said second pawl being engaged with said teeth of said ring gear when said ratchet mechanism is in said second position.   
     
     
       7. The multiplanar probe as defined in claim 6, wherein said means for displacing said ratchet mechanism comprises first and second bimorphic devices, each of said bimorphic devices being comprised of piezoelectric material which bends in response to application of an electrical pulse thereto, said first and second bimorphic devices being arranged to displace said ratchet mechanism between said first and second positions in response to electrical pulses applied thereto. 
     
     
       8. The multiplanar probe as defined in claim 7, further comprising detent means for preventing rotation of said ring gear during intervals between successive indexing steps, and spring means for urging said detent means into engagement with said teeth of said ring gear. 
     
     
       9. The multiplanar probe as defined in claim 6, further comprising position encoding means for detecting the angular position of said transducer array. 
     
     
       10. The multiplanar probe as defined in claim 6, wherein said first and second pawls are pivotably mounted on said ratchet mechanism, each of said pawls being rotatable over a predetermined angular range of less than 360°. 
     
     
       11. A multiplanar probe comprising, an array of ultrasonic transducers, each of said transducers including an output electrode, said probe further comprising: a ring gear affixed to said transducer array for rotating the transducer array about an axis of rotation, said ring gear being connected to said array and having a plurality of teeth distributed at equal angular intervals on its periphery;   indexing means for driving said ring gear to rotate in angular steps;   a housing, said probe being situated within said housing;   array stop means mounted on said periphery of said ring gear and extending radially outward beyond the radial extent of said teeth;   first and second stop pins mounted on said housing, said first stop pin being arranged to engage said array stop means when said transducer array is at a first angular position and said second stop pin being arranged to engage said array stop means when said transducer array is at a second angular position; and   feedback means for signaling impingement of said array stop means on said first or second stop pin to prevent actuation of said indexing means to rotate said ring gear beyond said first or second stop pin, respectively.